Herbicidal composition and method of use thereof

ABSTRACT

The present invention relates to a to a method of controlling the growth of weeds, in particular, large crabgrass and white clover, using a herbicidal composition comprising mesotrione and a triazolinone herbicide such as sulfentrazone or carfentrazone-ethyl. The invention also relates to the use of this composition.

The present invention relates to a herbicidal composition comprisingmesotrione and a triazolinone herbicide such as sulfentrazone orcarfentrazone-ethyl. The invention also relates to a method ofcontrolling the growth of weeds, in particular large crabgrass and whiteclover using the composition, and to the use of this composition.

The protection of crops from weeds and other vegetation that inhibitcrop growth is a constantly recurring problem in agriculture and turfmanagement. In addition, aesthetically, it may be of interest to removesuch unwanted weeds and vegetation, for example, when growing turf inareas such as golf courses, lawns and public parks. To help combat theseproblems, researchers in the field of synthetic chemistry have producedan extensive variety of chemicals and chemical formulations effective inthe control of such unwanted growth. Chemical herbicides of many typeshave been disclosed in the literature and a large number are incommercial use. Commercial herbicides and some that are still indevelopment are described in ‘The Pesticide Manual’, 13^(th) Edition,published 2003 by the British Crop Protection Council.

In some cases, herbicidal active ingredients have been shown to be moreeffective in combination than when applied individually, and this isreferred to as “synergism”, since the combination demonstrates a potencyor activity level exceeding that which it would be expected to havebased on knowledge of the individual potencies of the components. Thepresent invention resides in the discovery that mesotrione, or a salt ormetal chelate thereof, and sulfentrazone, already known individually fortheir herbicidal properties, display a synergistic effect when appliedin combination.

The herbicidal compounds forming the composition of this invention areindependently known in the art for their effects on plant growth. Theyare disclosed in ‘The Pesticide Manual’, ibid, and are also commerciallyavailable.

Mesotrione (2-(2′-nitro-4′-methylsulphonylbenzoyl)-1,3-cyclohexanedione)is a member of an important class of selective herbicides, thetriketones and works by affecting carotenoid biosynthesis. Inparticular, it inhibits the enzyme 4-hydroxyphenyl-pyruvate dioxygenase(it is an HPPD-inhibitor). In the acid form, its structure can berepresented as:

In addition to the acid form, mesotrione also forms salts and metalchelate, for example, a copper chelate. These metal chelates aredisclosed, inter alia, in U.S. Pat. No. 5,912,207 (the disclosure ofwhich is herein incorporated by reference) where they are shown to haveunexpectedly superior stability in certain environments when compared tounchelated mesotrione.

Mesotrione is best known for its ability to control a wide spectrum ofbroadleaf weeds at a wide range of growth stages when appliedpost-emergence on corn and turfgrass. It is typically used at a low rate(100-225 grams of active ingredient per hectare depending on herbicideformulation on application timing) to control weeds which are present atapplication and which emerge for up to four weeks afterwards. Onceapplied, mesotrione is rapidly absorbed by the leaves, shoots, roots andseeds. In susceptible weeds, it disrupts carotenoid biosynthesis, anessential process for plant growth and this leads to plant death. Unlikeweeds, corn plants and certain turfgrass species are able to toleratemesotrione by rapidly breaking down the active compound into inactivecompounds.

Triazolinone herbicides are selective herbicides which act by inhibitingphotosynthesis. There may be mentioned sulfentrazone,carfentrazone-ethyl, amicarbazone and azafenidin. In particular, theremay be mentioned sulfentrazone2′,4′-dichloro-5′-(4-difluoromethyl-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl)methanesulfonanilide.Its structure can be represented as:

Accordingly, the present invention provides a herbicidal compositioncomprising a herbicidally effective amount of a mixture of mesotrioneand a triazolinone herbicide.

In one embodiment of the invention, the triazolinone herbicide issulfentrazone, carfentrazone-ethyl, amicarbazone, thiencarbazone orazafenidin. In a particular embodiment, the triazolinone herbicide issulfentrazone.

The composition contains a herbicidally effective amount of acombination of mesotrione and a triazolinone. The term ‘herbicide’ asused herein denotes a compound which controls or modifies the growth ofplants. The term ‘herbicidally effective amount’ indicates the quantityof such a compound or combination of such compounds which is capable ofproducing a controlling or modifying effect on the growth of plants.Controlling or modifying effects include all deviation from naturaldevelopment, for example: killing, retardation, leaf burn, albinism,dwarfing and the like. For example, plants that are not killed are oftenstunted and non-competitive with flowering disrupted. The term ‘plants’refers to all physical parts of a plant, including seeds, seedlings,saplings, roots, tubers, stems, stalks, foliage and fruits.

It is noted that mesotrione is only one of a number of herbicides thatact as HPPD inhibitors. Other HPPD inhibitors are also known and may beused in the composition of the present invention in place of mesotrione.Suitably, other HPPD inhibitors for use in the present invention may beselected from the group consisting of triketones, isoxazoles, pyrazoles,benzobicyclon and ketospiradox. Further details of the individualcompounds which fall within the triketones, isoxazoles and pyrazoles maybe found in PCT Publication No. WO 2005/053407 (the disclosure of whichis herein incorporated by reference) but there may be mentionedsulcotrione, isoxaflutole, isoxachlortole, benxofenap, pyrazolynate andpyrazoxyfen. Further suitable HPPD inhibitors fur use in the presentinvention in place of mesotrione include tembotrione, topramezone, and acompound of the formula

As used herein, the designation ‘mesotrione’ includes the salts andchelated forms of mesotrione as well as the acid form and also includesany enolic tautomeric forms that may give rise to geometric isomers.Furthermore, in certain cases, the various substituents and/or chelatedforms may contribute to optical isomerism and/or stereoisomerism. Allsuch tautomeric forms, racemic mixtures and isomers are included withinthe scope of the present invention.

In one embodiment of the invention, the mesotrione is present as theacid form. In a further embodiment, mesotrione is present as a salt or ametal chelate.

Suitable salts of mesotrione include salts of cations or anions whichare known and accepted in the art for the formation of salts foragricultural or horticultural use. Such salts may be formed, forexample, using amines, alkali metal bases, alkaline earth metal basesand quaternary ammonium bases.

Metal chelates of 2-(substituted benzoyl)-1,3-cyclohexanedione compoundsincluding mesotrione are described, inter alia, in U.S. Pat. No.5,912,207. In one embodiment, suitable metal chelates of mesotrione havethe general structure:

wherein M represents a di- or trivalent metal ion.

Suitably, the di- or trivalent metal ion may be a Cu²⁺, Co²⁺, Zn²⁺,Ni²⁺, Ca²⁺, Al³⁺, Ti³⁺ or Fe³⁺ ion. More suitably, the metal ion may bea divalent transition metal ion such as Cu²⁺, Ni²⁺, Zn²⁺ and Co²⁺. Moresuitably the metal ion may be Cu²⁺ and Zn²⁺ and most suitably Cu²⁺.

Herbicidal metal chelates of mesotrione for use in this invention may beprepared by the methods described in the aforementioned US Patent, or bythe application and adaptation of known methods used or described in thechemical literature. In particular, any appropriate salt which would bea source of a di- or trivalent metal ion may be used to form the metalchelate of the dione compound in accordance with this invention.Particularly suitable salts include chlorides, sulphates, nitrates,carbonates, phosphates and acetates.

Suitably, the compositions of the invention comprise mesotrione and thetriazolinone herbicide in a synergistically effective amount. In thecompositions of this invention, the weight ratio of mesotrione to thetriazolinone herbicide at which the herbicidal effect is synergisticlies within the range of between about 1:100 and about 1:1. Preferably,the weight ratio of mesotrione to triazolinone herbicide is betweenabout 1:100 and about 1:2. More preferably, the weight ratio ofmesotrione to triazolinone herbicide is between about 1:50 and about1:5, with a weight ratio of about 1:12 being especially preferred.

The rate at which the composition of the invention is applied willdepend upon the particular type of weed to be controlled, the degree ofcontrol required and the timing and method of application. In general,the compositions of the invention can be applied at an application rateof between 0.005 kilograms/hectare (kg/ha) and about 5.0 kg/ha, based onthe total amount of active ingredient (mesotrione and triazolinoneherbicide) in the composition. An application rate of between about 0.1kg/ha and about 3.0 kg/ha is preferred, with an application rate ofbetween about 0.12 kg/ha and 1 kg/ha being especially preferred. It isnoted that the rates used in the examples below are glasshouse rates andare lower than those normally applied in the field as herbicide effectstend to be magnified in such conditions.

In a further aspect, the present invention provides a method ofcontrolling or modifying the growth of weeds comprising applying to thelocus of such weeds a herbicidally effective amount of a composition ofthe invention.

The composition of the invention may be used against a large number ofagronomically important weeds, including, but not limited to,monocotyledonous weeds such as Agrostis spp., Digitaria spp. (e.g. D.ischaemum, D. sanguinalis), Avena spp., Setaria spp., Lolium spp.,Echinochloa spp., Eleusine spp. (e.g. Eleusine indica), Scirpus spp.,Monochoria spp., Sagittaria spp., Bromus spp., Alopecurus spp., Sorghumhalepense, Rottboellia spp., Cyperus spp. (e.g. Cyperus esculentus) anddicotyledonous weeds such as Stellaria spp., Nasturtium spp., Sinapisspp., Solanum spp., Phaseolus spp., Taraxacum spp. (e.g. Taraxacumofficinale), Trifolium spp. (e.g. Trifolium repens), Abutilon spp., Sidaspp., Xanthium spp., Amaranthus spp., Chenopodium spp., Ipomoea spp.,Chrysanthemum spp., Galium spp., Viola spp. and Veronica spp.

More specifically, among the weeds which may be controlled by thecomposition of the invention, there may be mentioned monocotyledonousweeds such as grasses (e.g. large and smooth crabgrass, bent grass andnimbleweed) and dicotyledonous weeds such as dandelion, white and redclover, chickweed, henbit, corn speedwell, oxalis, buckhorn andbroadleaf plantain, dollar weed, FL pusley, lambsquarters, knotweed,ragweed, wild violets, pigweed and hedge weed. In a particularembodiment, the compositions of the invention may be used to controlmonocotyledonous weeds such as grasses. Suitably, the grass is largecrabgrass.

For the purposes of the present invention, the term ‘weeds’ includesundesirable crop species such as volunteer crops. For example, in thecontext of turf grass crops such as on a golf course, creeping bentgrassputting green turf can be considered a ‘volunteer’ if found in a fairwaysection where a different variety of grass is being cultivated. Theother grasses listed below can, similarly, be considered weeds whenfound in the wrong place.

The ‘locus’ is intended to include soil, seeds, and seedlings as well asestablished vegetation.

The benefits of the present invention are seen most when the pesticidalcomposition is applied to kill weeds in growing crops of useful plants:such as maize (corn) including field corn, pop corn and sweet corn;cotton, wheat, rice, oats, potato sugarbeet, plantation crops (such asbananas, fruit trees, rubber trees, tree nurseries), vines, asparagus,bushberries (such as blueberries), caneberries, cranberries, flax, grainsorghum, okra, peppermint, rhubarb, spearmint and sugarcane.

‘Crops’ are understood to also include various turf grasses including,but not limited to, the cool-season turf grasses and the warm-seasonturf grasses.

Cool season turfgrasses include, for example, bluegrasses (Poa L.), suchas Kentucky bluegrass (Poa pratensis L.), rough bluegrass (Poa trivialisL.), Canada bluegrass (Poa compressa L.) and annual bluegrass (Poa annuaL.); bentgrasses (Agrostis L.), such as creeping bentgrass (Agrostispalustris Huds.), colonial bentgrass (Agrostis tenius Sibth.), velvetbentgrass (Agrostis canina L.) and redtop (Agrostis alba L.); fescues(Festuca L.), such as tall fescue (Festuca arundinacea Schreb.), meadowfescue (Festuca elation L.) and fine fescues such as creeping red fescue(Festuca rubra L.), chewings fescue (Festuca rubra var. commutataGaud.), sheep fescue (Festuca ovina L.) and hard fescue (Festucalongifolia); and ryegrasses (Lolium L.), such as perennial ryegrass(Lolium perenne L.) and annual (Italian) ryegrass (Lolium multiflorumLam.).

Warm season turfgrasses include, for example, Bermudagrasses (Cynodon L.C. Rich), including hybrid and common Bermudagrass; Zoysiagrasses(Zoysia Willd.), St. Augustinegrass (Stenotaphrum secundatum (Walt.)Kuntze); and centipedegrass (Eremochloa ophiuroides (Munro.) Hack.).

In addition ‘crops’ are to be understood to include those crops thathave been made tolerant to pests and pesticides, including herbicides orclasses of herbicides (and, suitably, the herbicides of the presentinvention), as a result of conventional methods of breeding or geneticengineering. Tolerance to herbicides means a reduced susceptibility todamage caused by a particular herbicide compared to conventional cropbreeds. Crops can be modified or bred so as to be tolerant, for example,to HPPD inhibitors such as mesotrione, EPSPS inhibitors such asglyphosate, or to glufosinate. It is noted that corn is inherentlytolerant to mesotrione.

Suitably, the composition of the present invention is useful incontrolling the growth of undesirable vegetation by pre-emergence orpost-emergence application to the locus where control is desired,depending on the crop over which the combination is applied. In oneembodiment, the herbicidal composition of the invention is applied as apre-emergent application.

The compounds of the invention may be applied either simultaneously orsequentially. If administered sequentially, the components may beadministered in any order in a suitable timescale, for example, with nolonger than 24 hours between the time of administering the firstcomponent and the time of administering the last component. Suitably,all the components are administered within a timescale of a few hours,such as one hour. If the components are administered simultaneously,they may be administered separately or as a tank mix or as apre-formulated mixture of all the components or as a pre-formulatedmixture of some of the components tank mixed with the remainingcomponents.

In practice, the compositions of the invention are applied as aformulation containing the various adjuvants and carriers known to orused in the industry. The compositions of the invention may thus beformulated as granules (and, suitably, as stabilised granules, asdescribed below), as wettable powders, as emulsifiable concentrates, aspowders or dusts, as flowables, as solutions, as suspensions oremulsions, or as controlled release forms such as microcapsules. Theseformulations may contain as little as about 0.5% to as much as about 95%or more by weight of active ingredient. The optimum amount for any givencompound will depend on formulation, application equipment and nature ofthe plants to be controlled.

Wettable powders are in the form of finely divided particles whichdisperse readily in water or other liquid carriers. The particlescontain the active ingredient retained in a solid matrix. Typical solidmatrices include fuller's earth, kaolin clays, silicas and other readilywet organic or inorganic solids. Wettable powders normally contain about5% to about 95% of the active ingredient plus a small amount of wetting,dispersing or emulsifying agent.

Emulsifiable concentrates are homogeneous liquid compositionsdispersible in water or other liquid and may consist entirely of theactive compound with a liquid or solid emulsifying agent, or may alsocontain a liquid carrier, such as xylene, heavy aromatic naphthas,isophorone and other non-volatile organic solvents. In use, theseconcentrates are dispersed in water or other liquid and normally appliedas a spray to the area to be treated. The amount of active ingredientmay range from about 0.5% to about 95% of the concentrate.

Granular formulations include both extrudates and relatively coarseparticles and are usually applied without dilution to the area in whichsuppression of vegetation is desired. Typical carriers for granularformulations include fertiliser, sand, fuller's earth, attapulgite clay,bentonite clays, montmorillonite clay, vermiculite, perlite, calciumcarbonate, brick, pumice, pyrophyllite, kaolin, dolomite, plaster, woodflour, ground corn cobs, ground peanut hulls, sugars, sodium chloride,sodium sulphate, sodium silicate, sodium borate, magnesia, mica, ironoxide, zinc oxide, titanium oxide, antimony oxide, cryolite, gypsum,diatomaceous earth, calcium sulphate and other organic or inorganicmaterials which absorb or which can be coated with the active compound.Particularly suitable is a fertiliser granule carrier. Granularformulations normally contain about 5% to about 25% active ingredientswhich may include surface-active agents such as heavy aromatic naphthas,kerosene and other petroleum fractions, or vegetable oils; and/orstickers such as dextrins, glue or synthetic resins. Suitably, thegranular formulation may be a stabilised composition which comprises atleast one granular substrate material containing at least one metalchelate of mesotrione and a triazolinone herbicide. The granularsubstrate material can be one of the typical carriers mentioned aboveand/or can be a fertiliser material e.g. urea/formaldehyde fertilisers,urea, potassium chloride, ammonium compounds, phosphorus compounds,sulphur, similar plant nutrients and micronutrients and mixtures orcombinations thereof. The metal chelate of mesotrione and a triazolinoneherbicide may be homogeneously distributed throughout the granule or maybe spray impregnated or absorbed onto the granule substrate after thegranules are formed.

Dusts are free-flowing admixtures of the active ingredient with finelydivided solids such as talc, clays, flours and other organic andinorganic solids which act as dispersants and carriers.

Microcapsules are typically droplets or granules of the active materialenclosed in an inert porous shell which allows escape of the enclosedmaterial to the surroundings at controlled rates. Encapsulated dropletsare typically about 1 to 50 microns in diameter. The enclosed liquidtypically constitutes about 50 to 95% of the weight of the capsule andmay include solvent in addition to the active compound. Encapsulatedgranules are generally porous granules with porous membranes sealing thegranule pore openings, retaining the active species in liquid forminside the granule pores. Granules typically range from 1 millimetre to1 centimetre, preferably 1 to 2 millimetres in diameter. Granules areformed by extrusion, agglomeration or prilling, or are naturallyoccurring. Examples of such materials are vermiculite, sintered clay,kaolin, attapulgite clay, sawdust and granular carbon. Shell o membranematerials include natural and synthetic rubbers, cellulosic materials,styrene-butadiene copolymers, polyacrylonitriles, polyacrylates,polyesters, polyamides, polyureas, polyurethanes and starch xanthates.

Other useful formulations for herbicidal applications include simplesolutions of the active ingredients in a solvent in which it iscompletely soluble at the desired concentration, such as acetone,alkylated naphthalenes, xylene and other organic solvents. Pressurisedsprayers, wherein the active ingredient is dispersed in finely-dividedform as a result of vaporisation of a low boiling dispersant solventcarrier, may also be used.

Many of these formulations described above include wetting, dispersingor emulsifying agents. Examples are alkyl and alkylaryl sulphonates andsulphates and their salts, polyhydric alcohols; polyethoxylatedalcohols, esters and fatty amines. These agents, when used, normallycomprise from 0.1% to 15% by weight of the formulation.

Suitable agricultural adjuvants and carriers that are useful informulating the compositions of the invention in the formulation typesdescribed above are well known to those skilled in the art. Suitableexamples of the different classes are found in the non-limiting listbelow.

Liquid carriers that can be employed include water, toluene, xylene,petroleum naphtha, crop oil, acetone, methyl ethyl ketone,cyclohexanone, acetic anhydride, acetonitrile, acetophenone, amylacetate, 2-butanone, chlorobenzene, cyclohexane, cyclohexanol, alkylacetates, diacetonalcohol, 1,2-dichloropropane, diethanolamine,p-diethylbenzene, diethylene glycol, diethylene glycol abietate,diethylene glycol butyl ether, diethylene glycol ethyl ether, diethyleneglycol methyl ether, N,N-dimethyl formamide, dimethyl sulfoxide,1,4-dioxane, dipropylene glycol, dipropylene glycol methyl ether,dipropylene glycol dibenzoate, diproxitol, alkyl pyrrolidinone, ethylacetate, 2-ethyl hexanol, ethylene carbonate, 1,1,1-trichloroethane,2-heptanone, alpha pinene, d-limonene, ethylene glycol, ethylene glycolbutyl ether, ethylene glycol methyl ether, gamma-butyrolactone,glycerol, glycerol diacetate, glycerol monoacetate, glycerol triacetate,hexadecane, hexylene glycol, isoamyl acetate, isobornyl acetate,isooctane, isophorone, isopropyl benzene, isopropyl myristate, lacticacid, laurylamine, mesityl oxide, methoxy-propanol, methyl isoamylketone, methyl isobutyl ketone, methyl laurate, methyl octanoate, methyloleate, methylene chloride, m-xylene, n-hexane, n-octylamine,octadecanoic acid, octyl amine acetate, oleic acid, oleylamine,o-xylene, phenol, polyethylene glycol (PEG400), propionic acid,propylene glycol, propylene glycol monomethyl ether, p-xylene, toluene,triethyl phosphate, triethylene glycol, xylene sulfonic acid, paraffin,mineral oil, trichloroethylene, perchloroethylene, ethyl acetate, amylacetate, butyl acetate, methanol, ethanol, isopropanol, and highermolecular weight alcohols such as amyl alcohol, tetrahydrofurfurylalcohol, hexanol, octanol, etc. ethylene glycol, propylene glycol,glycerine, N-methyl-2-pyrrolidinone, and the like. Water is generallythe carrier of choice for the dilution of concentrates.

Suitable solid carriers include talc, titanium dioxide, pyrophylliteclay, silica, attapulgite clay, kieselguhr, chalk, diatomaxeous earth,lime, calcium carbonate, bentonite clay, fuller's earth, fertiliser,cotton seed hulls, wheat flour, soybean flour, pumice, wood flour,walnut shell flour, lignin and the like.

A broad range of surface-active agents are advantageously employed inboth said liquid and solid compositions, especially those designed to bediluted with carrier before application. The surface-active agents canbe anionic, cationic, non-ionic or polymeric in character and can beemployed as emulsifying agents, wetting agents, suspending agents or forother purposes. Typical surface active agents include salts of alkylsulfates, such as diethanolammonium lauryl sulphate; alkylarylsulfonatesalts, such as calcium dodecylbenzenesulfonate; alkylphenol-alkyleneoxide addition products, such as nonylphenol-C.sub. 18 ethoxylate;alcohol-alkylene oxide addition products, such as tridecylalcohol-C.sub. 16 ethoxylate; soaps, such as sodium stearate;alkylnaphthalenesulfonate salts, such as sodiumdibutylnaphthalenesulfonate; dialkyl esters of sulfosuccinate salts,such as sodium di(2-ethylhexyl)sulfosuccinate; sorbitol esters, such assorbitol oleate; quaternary amines, such as lauryl trimethylammoniumchloride; polyethylene glycol esters of fatty acids, such aspolyethylene glycol stearate; block copolymers of ethylene oxide andpropylene oxide; and salts of mono and dialkyl phosphate esters.

Other adjuvants commonly utilized in agricultural compositions includecrystallisation inhibitors, viscosity modifiers, suspending agents,spray droplet modifiers, pigments, antioxidants, foaming agents,light-blocking agents, compatibilizing agents, antifoam agents,sequestering agents, neutralising agents and buffers, corrosioninhibitors, dyes, odorants, spreading agents, penetration aids,micronutrients, emollients, lubricants, sticking agents, and the like.The compositions can also be formulated with liquid fertilizers orsolid, particulate fertiliser carriers such as ammonium nitrate, ureaand the like.

An important factor in influencing the usefulness of a given herbicideis its selectivity towards crops. In some cases, a beneficial crop issusceptible to the effects of the herbicide. To be effective, anherbicide must cause minimal damage (preferably no damage) to thebeneficial crop while maximizing damage to weed species which infest thelocus of the crop. To preserve the beneficial aspects of herbicide useand to minimize crop damage, it is known to apply herbicides incombination with an antidote if necessary. As used here in ‘antidote’describes a compound which has the effect of establishing herbicideselectivity, i.e. continued herbicidal phytotoxicity to weed species bythe herbicide and reduced or non-phytotoxicity to the cultivated cropspecies. The term ‘antidotally effective amount’ describes an amount ofan antidote compound which counteracts to some degree a phytotoxicresponse of a beneficial crop to an herbicide. If necessary or desiredfor a particular application or crop, the composition of the presentinvention may contain an antidotally effective amount of an antidote forthe herbicides of the invention. Those skilled in the art will befamiliar with antidotes which are suitable for use with mesotrione andtriazolinone herbicides and can readily determine an antidotallyeffective amount for a particular compound and application.

In addition, further, other biocidally active ingredients orcompositions may be combined with the herbicidal composition of thisinvention. For example, the compositions may contain, in addition tomesotrione and the triazolinone herbicide, other herbicides,insecticides, fungicides, bactericides, acaracides, nematicides and/orplant growth regulators, in order to broaden the spectrum of activity.

Each of the above formulations can be prepared as a package containingthe herbicides together with other ingredients of the formulation(diluents, emulsifiers, surfactants, etc.). The formulations can also beprepared by a tank mix method, in which the ingredients are obtainedseparately and combined at the grower site.

These formulations can be applied to the areas where control is desiredby conventional methods. Dust and liquid compositions, for example, canbe applied by the use of power-dusters, broom and hand sprayers andspray dusters. The formulations can also be applied from airplanes as adust or a spray or by rope wick applications. To modify or controlgrowth of germinating seeds or emerging seedlings, dust and liquidformulations can be distributed in the soil to a depth of at leastone-half inch below the soil surface or applied to the soil surfaceonly, by spraying or sprinkling. The formulations can also be applied byaddition to irrigation water. This permits penetration of theformulations into the soil together with the irrigation water. Dustcompositions, granular compositions or liquid formulations applied tothe surface of the soil can be distributed below the surface of the soilby conventional means such as discing, dragging or mixing operations.

The present invention can be used in any situation in which weed controlis desired, for example in agriculture, on golf courses, or in gardens.The present invention is particularly suitable for the selective controlof weeds such as large crabgrass in turfgrass. Mixtures of mesotrioneand a triazolinone herbicide coated on or impregnated in a fertilisergranule are particularly useful.

The following examples are for illustrative purposes only. The examplesare not intended as necessarily representative of the overall testingperformed and are not intended to limit the invention in any way. As oneskilled in the art is aware, in herbicidal testing, a significant numberof factors that are not readily controllable can affect the results ofindividual tests and render them non-reproducible. For example, theresults may vary depending on environmental factors, such as amount ofsunlight and water, soil type, pH of the soil, temperature and humidity,among others. Also, the depth of planting, the application rate ofindividual and combined herbicides, the application rate of anyantidote, and the ratio of the individual herbicides to one anotherand/or to an antidote as well as the nature of crops or weeds beingtested can affect the results of the test. Results may vary from crop tocrop within the crop varieties.

EXAMPLES Example 1 Control of Large Crabgrass with Mesotrione andSulfentrazone Applied Pre-Emergence

A glasshouse trial was carried out. Large crabgrass seeds were sown intostandard glasshouse potting mix (1:1 v/v Promix:Vero sand soil)contained in 10 cm square plastic pots. Treatments were replicated threetimes. Mesotrione (in the form Callisto® 480SE) was appliedpre-emergence to large crabgrass (Digitaria sanguinalis) at either 12 gai/ha or 24 g ai/ha with or without sulfentrazone (in the formAuthority®). When used, sulfentrazone was applied at a rate of 140 gai/ha or 280 g ai/ha. The adjuvant system was X-77 at 0.1% v/v indeionised water. 200 litres of herbicide/adjuvant system was used perhectare. General weed control was evaluated at 7 days after treatment(DAT). It is noted that all herbicides were applied at reduced fieldrates because herbicide effects are magnified in a glasshouseenvironment. Rates were chosen to give a 50 to 70% level of control withherbicides applied alone as this allows for detection of any synergisticeffect when tank mixtures are used.

It is noted that control of large crabgrass with the higher rate ofmesotrione alone was too high to allow for detection synergy whenmesotrione was mixed with sulfentrazone. The lower rate of mesotrionewas therefore used in this analysis. Synergy was observed for acombination of this lower rate of mesotrione with the lower rate ofsulfentrazone. Table 1 shows these results. The results were evaluatedusing the Colby formula. The expected result for (A+B) is(A+B)−(A×B/100) where A and B are the ‘observed’ results for A and B ontheir own. Control from the tank mixture is synergistic if the actualresult is significantly higher than the expected result (significancebased on Student-Newman-Keuls multiple range test).

TABLE 1 Plus Mesotrione at 12 g ai/ha Herbicide Rate (g ai/ha) ActualExpected Sulfentrazone 140 100 87.0

Sulfentrazone provided 75% control of large crabgrass (Digitariasanguinalis) on its own; mesotrione provided 50.0% control at the lowerrate. Using the Colby formula and Student-Newman-Keuls multiple rangetest, synergy was seen at these rates of mesotrione and sulfentrazone.

Example 2 Control of White Clover with Mesotrione and CarfentrazoneApplied Pre-Emergence

A glasshouse trial was set up as described in Example 1, except usingcarfentrazone instead of sulfentrazone, Trifolium repens (white clover)instead of large crabgrass, and different herbicide rates. The resultsare given in Table 2.

TABLE 2 Plus Mesotrione Plus Mesotrione Rate at 25 g ai/ha at 50 g ai/haHerbicide (g ai/ha) Actual Expected Actual Expected Carfentrazone 18 5550 75 62 Carfentrazone 36 73 49 85 61

Example 3 Control of White Clover with Mesotrione and CarfentrazoneApplied Post-Emergence

A glasshouse trial was set up as described in Example 2, except usingapplying the mixture post emergence rather than pre-emergence. Theresults are given in Table 3.

TABLE 3 Plus Mesotrione Plus Mesotrione Rate at 100 g ai/ha at 150 gai/ha Herbicide (g ai/ha) Actual Expected Actual Expected Carfentrazone18 70 43 93 65 Carfentrazone 36 72 53 93 71

Although the invention has been described with reference to preferredembodiments and examples thereof, the scope of the present invention isnot limited only to those described embodiments. As will be apparent topersons skilled in the art, modifications and adaptations to theabove-described invention can be made without departing from the spiritand scope of the invention, which is defined and circumscribed by theappended claims. All publications cited herein are hereby incorporatedby reference in their entirety for all purposes to the same extent as ifeach individual publication were specifically and individually indicatedto be so incorporated by reference.

1. A method for controlling or modifying the growth of large crabgrassor white clover, comprising pre-emergence application of a herbicidallyeffective amount of a composition comprising a herbicidally effectiveamount of a mixture of mesotrione and a triazolinone herbicide to thelocus of the large crabgrass or white clover.
 2. The method of claim 1,wherein the large crabgrass or white clover is present in turfgrass. 3.The method of claim 1, wherein the triazolinone herbicide issulfentrazone.
 4. The method of claim 1, wherein the triazolinoneherbicide is carfentrazone.
 5. The method of claim 1, wherein mesotrioneis in a chelated form.
 6. The method of claim 5, wherein the copperchelate of mesotrione is used.
 7. The method of claim 1, wherein thecombined amount of mesotrione and triazolinone herbicide applied to thelocus of the weeds is between about 0.005 kg/ha and about 5 kg/ha. 8.The method of claim 7, wherein the combined amount of mesotrione andtriazolinone herbicide applied to the locus of the weeds is betweenabout 0.1 kg/ha and about 3 kg/ha.
 9. The method of claim 8, wherein thecombined amount of mesotrione and triazolinone herbicide applied to thelocus of the weeds is between about 0.15 kg/ha and about 1 kg/ha. 10.The method of claim 1, wherein the weight ratio of mesotrione totriazolinone herbicide is between about 1:100 and about 1:1.
 11. Themethod of claim 10, wherein the weight ratio of mesotrione totriazolinone herbicide is between about 1:100 and about 1:2.
 12. Themethod of claim 11, wherein the weight ratio of mesotrione totriazolinone herbicide is between about 1:50 and about 1:5.
 13. Themethod of claim 1, wherein the mixture is impregnated in or coated on afertiliser granule.
 14. (canceled)